Silhouette illuminated instrument panel display apparatus

Abstract

 An improved vehicle display apparatus in which both the display and pointer (22) are illuminated for low ambient driver viewing by a single electroluminescent (EL) lamp (14) mounted on the rear face of the display. A generally opaque applique (18) includes a translucent region (38) in registry with the active area (16) of the EL lamp, and bright opaque graphic symbols (20) painted or deposited onto a surface of the applique within the translucent region. A pointer disposed in proximity to the front surface of the applique is provided with juxtaposed bright opaque (46,48) and transparent (42) regions or stripes. In high ambient lighting conditions when the EL lamp is not lit, a viewer of the display perceives the bright opaque graphic symbols and pointer stripes against the relatively dark translucent background regions of the applique. In low ambient lighting conditions when the EL lamp is lit, the viewer perceives the opaque graphic symbols and pointer stripes in silhouette against the relatively bright translucent regions of the applique and pointer, respectively.

Description

[0001] This invention relates to instrument panel display apparatus for a motor vehicle, and more particularly, to an illuminated display apparatus which causes the display graphics and pointer to appear in silhouette when the display is illuminated for driver viewing during low ambient lighting conditions.

[0002] Illumination of instrument panel nonemissive display apparatus for driver viewing during low ambient lighting conditions is typically achieved with front-lighting or flood-lighting techniques in which a light source is directed onto the front face of the display. Unfortunately, this technique causes significant heating and the display pointer tends to shadow the face of the display. As an alternative, the display may be back-lit by directing a light source onto the rear face of the display, thereby lighting portions of the display which are normally dark, but then the pointer must be separately lit by either front-lighting or light-piping techniques. Front-lighting has drawbacks in terms of heating and shadowing, as described above, and tends to defeat the back-lighting effect, while light-piping has drawbacks in terms of weight, cost and packaging.

[0003] An instrument panel display apparatus in accordance with the present invention is characterised by the features specified in the characterising portion of claim 1.

[0004] The present invention is directed to an improved instrument panel display apparatus in which both the instrument panel display apparatus and its pointer are illuminated for low ambient driver viewing by a single electroluminescent (EL) lamp mounted on the rear face of a generally opaque applique having a translucent region in registry with an active region of the EL lamp, and bright opaque graphic symbols painted or deposited onto a surface of the applique within the translucent region. The pointer is disposed in proximity to the front surface of the applique and may be provided with juxtaposed bright opaque and translucent/transparent stripes.

[0005] In high ambient lighting conditions, the EL lamp is not lit and the bright opaque portions of the instrument panel display apparatus dominate. In this case, a viewer of the instrument panel display apparatus perceives the bright opaque graphic symbols and pointer stripes against the relatively dark translucent background regions of the applique. In low ambient lighting conditions, the EL lamp is lit and the translucent portions of the instrument panel display apparatus dominate. In this case, the viewer perceives the opaque graphic symbols and opaque pointer stripes in silhouette against the relatively bright translucent regions of the applique and pointer, respectively. No separate pointer lighting is required since light from the translucent region passes through the translucent/transparent stripe of the pointer.

[0006] Thus, the instrument panel display apparatus of the present invention overcomes the drawbacks of the prior displays. The EL lamp produces much less heat than other, more directed light sources, the pointer does not shadow the face of the instrument panel display apparatus, the cost is relatively low, and packaging is simplified because light-piping is not required.

[0007] The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Figure 1 is an exploded view of an instrument panel display apparatus according to this invention, including the pointer and driver, the EL lamp and the applique;

Figure 2 is a schematic illustration of the applique of Figure 1;

Figure 3 is an enlarged view of the pointer of Figure 1; and

Figures 4 and 5 illustrate a portion of the instrument panel display apparatus as perceived by a viewer during high and low ambient lighting conditions, respectively.

[0008] Referring to Figure 1, the reference numeral 10 generally designates the elements of an instrument panel display apparatus according to this invention. The instrument panel display apparatus 10 comprises a rotary actuator 12, such as a conventional air core gauge mechanism, an EL lamp 14 having an active light emitting region 16, an applique 18 having bright opaque graphic symbols 20 painted or deposited on the surface thereof, and a pointer 22 which is rotatable. The applique 18 is mounted on the EL lamp 14 such that the graphic symbols 20 fall within the active light emitting region 16. An output shaft 24 of rotary actuator 12 extends through central openings 26, 28 in EL lamp 14 and applique 18 for attachment to a hub 30 of pointer 22.

[0009] Referring additionally to Figure 2, it is seen that the applique 18 is a multi-layered film or film means. The base film 32 preferably comprises a translucent or neutral density material, such as 35% transmissivity polycarbonate. A rear face 34 (the surface which faces away from the vehicle occupant) of the base film 32 is coated with an opaque material 36 in the areas which would lie outside the active light emitting region 16 of EL lamp 14, leaving a translucent region 38 which corresponds to and lies in registry with the active light emitting region 16 in the assembled display. The graphic symbols 20 are painted or deposited on a front face 40 (the surface which faces towards the vehicle occupant) of the base film 32, using a bright opaque material. In the preferred embodiment, the white and/or orange colour material is used to form the graphic symbols 20 in order to achieve high contrast against the relatively dark translucent region 38 when the EL lamp 14 is not lit.

[0010] As seen more clearly in Fiqure 3, the pointer 22 is predominantly opaque, with the exception of a generally transparent region 42 along the length of the pointer stem 44. Alternatively, the transparent region 42 may be formed by a physical opening in the pointer stem 44. As with the graphic symbols 20, the opaque area of the pointer 22 is coloured brightly to achieve high contrast against the relatively dark translucent region 38 of applique 18 when the EL lamp 14 is not lit. In the preferred embodiment, the opaque areas of the pointer 22 are white or orange. To a viewer of the instrument panel display apparatus 10, the pointer stem 44 of pointer 22 is thus perceived as a pair of like-colour stripes 46 and 48 separated by a central contrasting stripe 43.

[0011] Figures 4 and 5 illustrate a viewers perception of the instrument panel display apparatus 10 in high and low ambient lighting conditions, respectively. It is assumed that the EL lamp 14 is unlit in the high ambient lighting conditions of Figure 4, and lit in the low ambient lighting conditions of Figure 5.

[0012] In the high ambient lighting conditions of Figure 4, the bright opaque portions of the instrument panel display apparatus 10. dominate the perception of the viewer. In this case, the viewer perceives the (bright opaque) graphic symbols 20 and (bright opaque) like-colour stripes 46, 48 of the pointer 22 against the relatively dark translucent region 38 of the applique 18. The central contrasting stripe 43 defined by the transparent region 42 appears just as dark as the translucent region 38.

[0013] In the low ambient lighting conditions of Figure 5, the translucent and transparent portions of the instrument panel display apparatus 10 dominate the perception of the viewer. In this case, the viewer perceives the graphic symbols 20 and like-colour stripes 46, 48 in silhouette against the relatively bright translucent and transparent regions 38 and 42 of applique 18 and pointer 22, respectively.

[0014] If desired, opaque graphic symbols may also be painted or deposited on the rear face 34 of the base film 32 within the translucent region 38, as indicated by the reference numeral 50 in Figure 2. Such opaque graphic symbols 50 would not be perceived by a viewer during high ambient conditions when the EL lamp 14 is unlit (especially if the symbol colour is not highly contrasted with the dark translucent region 38), but would be perceived in silhouette against the translucent region 38 during low ambient conditions when the EL lamp 14 is lit as indicated by the minor division graphic marks (50) in Figure 5.

[0015] Additionally, it may be desired to eliminate the transparent region 42 of pointer 22, and instead coat the entire face of the pointer 22 with a bright opaque material. In this case, the entire pointer 22 would be perceived in silhouette against the bright translucent region 38 when the EL lamp 14 is lit during low ambient lighting conditions.

[0016] In the transition between low and high ambient lighting conditions, such as at dawn or dusk, the contrast between the graphic symbols 20 and the translucent region 38 is somewhat decreased when the EL lamp 14 is lit. The reduced contrast is acceptable, but may be improved by employing a fluorescent opaque material to paint/coat the graphic symbols 20 and pointer 22.

Claims

1. An instrument panel display apparatus for a motor vehicle adapted to be viewed by a vehicle occupant during both high and low ambient lighting conditions, comprising an electroluminescent lamp (14) having an active region (16) which when activated emits diffuse light onto a surface (34) of a film means (18) which faces away from the vehicle occupant; characterised in that the film means (18) includes a translucent region (38) and bright opaque graphic symbols (20) formed on a surface (40) of the translucent region which faces toward the vehicle occupant so that in high ambient lighting conditions, the vehicle occupant perceives the bright opaque graphic symbols against the translucent region; and in that the active region can emit diffuse light at least in the vicinity of the translucent region, so that when the electroluminescent lamp is activated during low ambient lighting conditions, the vehicle occupant perceives the bright opaque graphic symbols in silhouette against the lighted translucent region of the film means.

2. An instrument panel display apparatus as claimed in claim 1, further comprising a pointer (22) disposed in proximity to the surface (40) of the translucent region (38) of the film means (18) facing the vehicle occupant between the vehicle occupant and the film means, the pointer having a stem (44) which is brightly coloured and opaque and which (1) is readily perceived by the vehicle occupant against the translucent region during high ambient lighting conditions when the electroluminescent lamp (14) is not activated, but (2) is silhouetted against the lighted translucent region of the film means when the electroluminescent lamp is activated during low ambient lighting conditions.

3. An instrument panel display apparatus as claimed in claim 2, wherein the stem (44) of the pointer (22) is defined by a pair of brightly coloured opaque regions (46,48) separated by a generally transparent region (42), so that the transparent region appears (1) dark in high ambient lighting conditions when the electroluminescent lamp (14) is not activated, and (2) lighted in low ambient lighting conditions when the electroluminescent lamp is activated.

4. An instrument panel display apparatus as claimed in any one of claims 1 to 3, wherein the film means (18) includes opaque graphic symbols (50) formed within the translucent region (38) on the surface (34) thereof which faces away from the vehicle occupant, so that such symbols (1) are not perceived by the vehicle occupant in high ambient lighting conditions when the electroluminescent lamp (14) is not activated, but (2) are perceived in silhouette against the translucent region in low ambient lighting conditions when the electroluminescent lamp is activated.

Drawing